She tried arguing that she “faints,” and has anxiety, and even that her boy victim had enjoyed it.

But there was no mercy this morning for Lina Sinha, the beautiful former headmistress of an Upper East Side Montessori school, who was finally sent away to serve at least 2 1/3 years in prison for her twisted and damaging sex affair with a student who was just 13.

“This is a woman of every advantage, and she preyed on her victim for years,” Manhattan Supreme Court Justice Carol Berkman said as the predatory ex-principal stared glumly down at the defense table.

“She hijacked his life as a child,” the judge said of the victim, who grew up to be a New York City cop and had compellingly taken the witness stand, describing years of trysts on class furniture and in a field trip van with the Montessori School of New York headmistress he called “Miss Sinha.”

“She did try to destroy his life,” the judge said. “So time has passed, but the victim has not regained the childhood the defendant has stolen for him, and I presume he never will.”

Sinha, 46, had until today remained free on bail, pending appeal, for the five years since a Manhattan jury convicted her of a depraved predation that might never have been exposed.

The victim only came forward as a police officer in training, after he finally broke off their nine-year “relationship” in 2004 and Sinha embarked on a rampage of vengeance against her former boy-toy, including making bogus accusations of assault and rape and repeated 911 calls and Civilian Complaint Review Board allegations.

“This case came at great personal embarrassment to him,” assistant district attorney Robert Hettleman, chief of the Manhattan DA’s child abuse unit, said of the victim, whose courage he praised.

The victim, whose name is being withheld, was a Queens-based, 24-year-old rookie in 2007, when he testified against Sinha, and remains a cop serving the public, Hettleman said.

Since the conviction, Sinha has been working for various charities, playing tennis and even running the New York City marathon, according to her website, Hettleman noted. But life for the victim and a second boy student — on whose rape counts the original jury hung — have been far from fun and games, the prosecutors said.

“I was in contact with him for years,” after the conviction, the prosecutor said of the victim cop. “It’s been very difficult for him in the interim.”

Sinha spoke briefly, and tearfully, at the proceeding, wasting not a word on apologies or regrets. Instead, she went on about how difficult the past eight years have been for her and her family, and the great sacrifices she had made to become an educator, given her family’s money and the “the many door open to me.”

“Most people thought I did a very good job,” in education, she told the judge. “If you deem it fit for me to go to prison, then that is what I will do,” she said. “I have gone through their life savings,” she complained, referring to her family. “I have gone through my life savings a long time ago.”

Sinha tried through veteran defense lawyer Gerald Shargel to argue for a reduction in sentence. She suffers glaucoma and diabetes, and has fainting spells and anxiety problems, Shargel told the judge.

“The punishment should fit the crime,” he said, referring to the conduct as “a love affair” and alluding to trial testimony in which the cop had admitted keeping the relationship secret as a boy because he’d enjoyed it and didn’t want it to stop.

“There was a love affair that continued,” the lawyer told the judge. “You heard the victim say he enjoyed the relationship. He found the relationship pleasurable. He expressed no damage, no harm.

“If every situation of love gone wrong and retaliatory behavior was prosecuted, they’d have to build more prisons,” Shargel argued.

“This was an extended situation,” the judge countered. “Until he was of, quote, legal age he was still being abused, overpowered psychologically…I think the defendant’s sentence is actually remarkably lenient given the continuing offenses.”